Subaru brat transmission swap 4 speed to five speed?

[Gone Fishing]

I have an 82 subaru brat I picked up for cheap. It has a 4 speed manual in it. I was at a wrecker today and they had only one subaru in my year range. It had the double headlights so im thinking mid 80s. It had the same carbed engine as mine except equipped with A/C. It also had a five speed manual trans. The car it is off of is a 2wd drive and the cv axles go through the transmission the same as mine but nothing is attached to the tail shaft. Will this trans work with my car that has a driveshaft for the rear wheels? I'm thinking it's just capped off but will have to take a closer look. Anyone know much about compatibility in older subarus?